The 31-year-old followed up his first-innings 85 with an even grittier knock in the second dig, twice jumping in the air in celebration and acknowledging teammates and his wife Rachel, who shed tears of pride and joy, as he brought up triple figures off 224 balls with a single after lunch.

It's just the fifth century by an Australian in the fourth innings of a Test in Asia, following Bob Simpson (115 v Pakistan in 1964), Mark Taylor (102 not out v India in 1998), Ricky Ponting (118 not out v Bangladesh in 2006) and David Warner (112 v Bangladesh last year).

Khawaja celebrates his Dubai century // Getty

Much had been made of Khawaja's struggles on the subcontinent having never managed a score of more than 26 in nine previous Test innings there before this Test. He had also been dropped mid-tour the past two times he's played there (in Sri Lanka in 2016 and in Bangladesh last year).

But Khawaja, against the country of his birth, has lived up to Ricky Ponting's billing as his country's "best batsman by a street" in a side without Steve Smith and David Warner.

Not only has he more than doubled his entire run tally in Asian Tests in one match, he's also batted for longer in this Test (594 minutes at the time of his ton) than he has in his other nine Test innings on the subcontinent put together.

Few gave Australia much hope of denying Pakistan victory in the series-opener after their extraordinary collapse of 10-60 on day three. But from the start of Australia's fourth innings. Khawaja looked intent on – and capable of – batting out the best part of five sessions to secure a draw.

Following an 87-run partnership with debutant Aaron Finch (backing up their 145-run stand in the first innings), Khawaja held firm late on day four as Abbas ripped through Australia's top order with three wickets in seven balls including both Marsh brothers for ducks.

Day wrap: Fighting Aussies face up to salvage job

He then found a willing ally in the debutant Head, with the two left-handers safely ensuring their side's passage to stumps on Wednesday, before the pair then went unbeaten through the first session on day five.

While defence was the backbone to Khawaja's resistance, his willingness to reverse sweep Yasir Shah out of the rough ensured he didn’t got bogged down.

He had a fascinating battle early on day five with Abbas, with the right-armer beating Khawaja's outside edge on a handful of occasions and offering a few choice words, but the Queenslander was happy to look ugly on occasions to get through.

His hundred also marks a successful return to the opening position, forging a successful bond with Finch after moving up there from No.3 for this Test. Khawaja struck 79 not out and 145 in two previous Test innings filling in at the top.

Aussies ride their luck as Pakistan rue non-reivew

Ahead of the series, Ponting predicted Khawaja to overcome his struggles on the subcontinent as long as he was given some certainty over his spot.

"There's been lots of different discussions over the last couple of years about Khawaja and how to get the get the best out of him," the former Test skipper told cricket.com.au last month. "(People wonder), 'is he an Australian Test match player only? Do we just not pick him on the subcontinent?'"

"I just think you've got to keep picking him – with Warner and those guys out, he's clearly our best batsman by a street.

"The more he can play in those conditions, the more he'll start to work it out.

"It's difficult. I was a bit the same; the first few tours I had to India, I struggled. But the more I played, the more I learned about how I was going to survive and how I was going to cope. The last couple of tours I had there were some of the best I ever had.